The mirror effect is recognition memory refers to the fact that, with several different classes of stimuli, performance on new items from each class mirrors (is orrelated with) performance on the corresponding classes of old items. Classes of stimuli that are accurately recognized as old when old are also accurately recognized as new when new; those that are poorly recognized as old when old are also poorly recognize( s new when new. The purpose of the proposed work is to explore further that regularity theory for this effect is developed--attention/likelihood theory. The theory covers he known regularities that are associated with the effect and predicts certain other, new regularities. These are tested in a series of experiments on the effects f forgetting, training, speed-accuracy trade-off. The proposed 'Work has strong implications for work on the effects of normal aging on memory, age related dysfunctions (e.g., senile dementia) as well as other memory dysfunctions (e.g., anterograde amnesias such as those part of the Korsakoff Syndrome).